Surgical device with powered articulation wrist rotation

ABSTRACT

A surgical instrument for treating tissue, the instrument including a housing and a shaft with an articulating portion and an end effector. The surgical instrument including a first casing connected to and rotatable with the proximal end of said shaft with an internal frame housed within the first casing and a plurality of posts supported by the internal frame and connected on their distal ends to at least one drive wire, and connected on their proximal ends to a threaded shaft; and a second casing connected to the first casing and rotatable therewith, said second casing housing the threaded shafts. The surgical instrument includes a first electric motor driving a first gear interfacing with the threaded shafts such that a first pair of the plurality of threaded shafts rotate in the same direction and cause the articulating portion to articulate in a first plane.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 13/668,346, filed Nov. 5, 2012, which claims the benefit of andpriority to U.S. Provisional Application Ser. No. 61/560,456, filed onNov. 16, 2011, the entire contents of which are incorporated herein byreference.

BACKGROUND

The present disclosure relates to surgical devices and moreparticularly, the present disclosure relates to a powered surgicaldevice having a motorized articulation and rotation system.

TECHNICAL FIELD

Many surgical devices utilize both mechanical clamping action andelectrical energy to effect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue. As an alternative toopen forceps for use with open surgical procedures, many modern surgeonsuse endoscopes and endoscopic instruments for remotely accessing organsthrough smaller, puncture-like incisions. As a direct result thereof,patients tend to benefit from less scarring and reduced healing time.

Generally, endoscopic surgery involves incising through body walls forexample, viewing and/or operating on the ovaries, uterus, gall bladder,bowels, kidneys, appendix, etc. There are many common endoscopicsurgical procedures, including arthroscopy, laparoscopy (pelviscopy),gastroentroscopy and laryngobronchoscopy, just to name a few. Typically,trocars are utilized for creating the incisions through which theendoscopic surgery is performed.

Trocar tubes or cannula devices are extended into and left in place inthe abdominal wall to provide access for endoscopic surgical tools. Acamera or endoscope is inserted through a relatively large diametertrocar tube which is generally located at the naval incision, andpermits the visual inspection and magnification of the body cavity. Thesurgeon can then perform diagnostic and therapeutic procedures at thesurgical site with the aid of specialized instrumentation, such as,forceps, cutters, applicators, and the like which are designed to fitthrough additional cannulae. Thus, instead of a large incision(typically 12 inches or larger) that cuts through major muscles,patients undergoing endoscopic surgery receive more cosmeticallyappealing incisions, between 5 and 10 millimeters in size. Recovery is,therefore, much quicker and patients require less anesthesia thantraditional surgery. In addition, because the surgical field is greatlymagnified, surgeons are better able to dissect blood vessels and controlblood loss.

In continuing efforts to reduce the trauma of surgery, interest hasrecently developed in the possibilities of performing procedures todiagnose and surgically treat a medical condition without any incisionin the abdominal wall by using a natural orifice (e.g., the mouth oranus) to access the target tissue. Such procedures are sometimesreferred to as endoluminal procedures, transluminal procedures, ornatural orifice transluminal endoscopic surgery (“NOTES”). Although manysuch endoluminal procedures are still being developed, they generallyutilize a flexible endoscope instrument or flexible catheter to provideaccess to the tissue target tissue. Endoluminal procedures have beenused to treat conditions within the lumen including for example,treatment of gastroesophageal reflux disease in the esophagus andremoval of polyps from the colon. In some instances, physicians havegone beyond the luminal confines of the gastrointestinal tract toperform intra-abdominal procedures. For example, using flexibleendoscopic instrumentation, the wall of the stomach can be punctured andan endoscope advanced into the peritoneal cavity to perform variousprocedures.

Using such endoluminal techniques, diagnostic exploration, liver biopsy,cholecystectomy, splenectomy, and tubal ligation have reportedly beenperformed in animal models. After the intra-abdominal intervention iscompleted, the endoscopic instrumentation is retracted into the stomachand the puncture closed. Other natural orifices, such as the anus orvagina, may also allow access to the peritoneal cavity.

As mentioned above, many endoscopic and endoluminal surgical procedurestypically require cutting or ligating blood vessels or vascular tissue.However, this ultimately presents a design challenge to instrumentmanufacturers who must attempt to find ways to make endoscopicinstruments that fit through the smaller cannulae. Due to the inherentspatial considerations of the surgical cavity, surgeons often havedifficulty suturing vessels or performing other traditional methods ofcontrolling bleeding, e.g., clamping and/or tying-off transected bloodvessels. By utilizing an endoscopic electrosurgical forceps, a surgeoncan cauterize, coagulate/desiccate and/or simply reduce or slow bleedingsimply by controlling the intensity, frequency and duration of theelectrosurgical energy applied through the jaw members to the tissue.Most small blood vessels, i.e., in the range below two millimeters indiameter, can often be closed using standard electrosurgical instrumentsand techniques. However, if a larger vessel is ligated, it may benecessary for the surgeon to convert the endoscopic procedure into anopen-surgical procedure and thereby abandon the benefits of endoscopicsurgery. Alternatively, the surgeon can seal the larger vessel or tissueutilizing specialized vessel sealing instruments.

It is thought that the process of coagulating vessels is fundamentallydifferent than electrosurgical vessel sealing. For the purposes herein,“coagulation” is defined as a process of desiccating tissue wherein thetissue cells are ruptured and dried. “Vessel sealing” or “tissuesealing” is defined as the process of liquefying the collagen in thetissue so that it reforms into a fused mass. Coagulation of smallvessels is sufficient to permanently close them, while larger vesselsneed to be sealed to assure permanent closure. Moreover, coagulation oflarge tissue or vessels results in a notoriously weak proximal thrombushaving a low burst strength whereas tissue seals have relatively highburst strength and may be effectively severed along the tissue sealingplane.

More particularly, in order to effectively seal larger vessels (ortissue) two predominant mechanical parameters are accuratelycontrolled—the pressure applied to the vessel (tissue) and the gapdistance between the electrodes—both of which are affected by thethickness of the sealed vessel. More particularly, accurate applicationof pressure is important to oppose the walls of the vessel; to reducethe tissue impedance to a low enough value that allows enoughelectrosurgical energy through the tissue; to overcome the forces ofexpansion during tissue heating; and to contribute to the end tissuethickness which is an indication of a good seal. It has been determinedthat a typical fused vessel wall is optimum between 0.001 and 0.006inches. Below this range, the seal may shred or tear and above thisrange the lumens may not be properly or effectively sealed.

With respect to smaller vessels, the pressure applied to the tissuetends to become less relevant whereas the gap distance between theelectrically conductive surfaces becomes more significant for effectivesealing. In other words, the chances of the two electrically conductivesurfaces touching during activation increases as vessels become smaller.

It has been found that the pressure range for assuring a consistent andeffective seal is between about 290 kPa to about 1570 kPa and,desirably, within a working range of 680 kPa to 1275 kPa. Manufacturingan instrument which is capable of providing a closure pressure withinthis working range has been shown to be effective for sealing arteries,tissues and other vascular bundles.

Various force-actuating assemblies have been developed in the past forproviding the appropriate closure forces to effect vessel sealing. Forexample, commonly-owned U.S. patent application Ser. Nos. 10/460,926 and11/513,979 disclose two different envisioned actuating assemblies, thecontents of both of these applications are hereby incorporated byreference herein.

During use, one noted challenge for surgeons has been the inability tomanipulate the end effector assembly of the vessel sealer to grasptissue in multiple planes, i.e., off-axis, while generating theabove-noted required forces to affect a reliable vessel seal. It hastherefore become desirable to develop an endoscopic or endoluminalvessel sealing instrument which includes an end effector assemblycapable of being manipulated along multiple axes to enable the surgeonto grasp and seal vessels lying along different planes within a surgicalcavity.

Two examples of devices for off axis articulation of an end effector aredescribed in commonly assigned U.S. Published Patent Application Nos.2010/0076433 and 2010/0179540, the contents of both are incorporated byreference.

As described in the '433 application, endoluminal procedures oftenrequire accessing tissue deep in tortuous anatomy of a natural lumenusing a flexible catheter or endoscope. Conventional vessel sealingdevices may not be appropriate for use in some endoluminal proceduresbecause of a rigid shaft that can not easily negotiate the tortuousanatomy of a natural lumen In view of this, the '433 applicationdiscloses an endoscopic vessel sealer having a flexible articulatingshaft. However, the endoscopic vessel sealer of the '433 applicationrequired manual inputs from the physician or surgeon to cause the endeffector to articulate and rotate the end effector through the use ofrotating knobs formed integrally with the housing. There are disclosedseparate knobs for articulation and rotation. While the inclusion ofboth articulation and rotation allows for nearly complete wrist likearticulation of the end effector, this concept required the use of twohands for effective operation; one hand to hold the instrument and oneto turn rotational and/or articulation wheels.

Similarly, the '540 application teaches the use of either two or fourcontrol wires to effectuate articulation of the end effector in multipleplanes. However, the '540 application also required the surgeon toemploy both hands for effective operation, Further, while the use offour wires enabled multi-plane movement, the systems employed tosynchronize the movement of the articulating portion of the shaft, weremanual and relied on the skill of the surgeon.

A one-handed design for an endoscopic surgical device has also beencontemplated by the assignee of the instant application. For example,commonly assigned U.S. Published Patent Application No. 2009/0054734,the contents of which are incorporated by reference, there is discloseda one-handed surgical device enabling the surgeon to articulate the endeffector in combination with rotation of the device such that anapproximation of wrist-like movement is possible. However, as disclosedin the '734 Publication, to accomplish the articulation of the endeffector, a proximal end of the surgical device must itself be moved offaxis. As can be readily understood by those of relevant skill in theart, the necessity of such off axis movement on the proximal end of thesurgical device can result in interference of the device with othersurgical tools which are also competing for the limited space availablethrough a single access port. Accordingly, while one-handed operation ispossible, the interference with other tools presents additionaldifficulties for the surgeon.

It is therefore desirable to develop an endoscopic or endoluminal vesselsealing instrument having a flexible shaft capable of insertion in aflexible endoscope or catheter which can be operated by one hand of thesurgeon. It is also desirable to develop such an end effectorincorporated into a housing allowing the surgeon to perform all thenecessary articulation of the end effector, while employing just asingle hand, and without necessitating off-axis movement of a proximalend of the surgical device, thus allowing the surgeon to utilize theother hand for use of other tools without compromising the spaceavailable for such tools.

SUMMARY

One aspect of the present disclosure is directed to a surgicalinstrument for treating tissue. The instrument includes a housing havinga shaft extending there from, the shaft includes at least anarticulating portion and an end effector. Connected to, and rotatablewith, the proximal end of the shaft is a first casing. An internal frameis housed within the first casing. A plurality of posts, are supportedby the internal frame and connected on their distal ends to at least onedrive wire, and connected on their proximal ends to a threaded shaft. Asecond casing is connected to the first casing and rotatable therewith,the second casing houses the threaded shafts. A first electric motordrives a first gear, the first gear interfaces with the threaded shaftssuch that a first pair of the plurality of threaded shaft rotate in thesame direction. A second electric motor drives a second gear, saidsecond gear causes the connected shaft and first and second casings torotate about a common axis. Driving the first gear in a first directioncauses said articulating portion to articulate in a first plane.

The surgical instrument may further includes a third electric motordriving a third gear, the third gear driving at least a second pair ofthe plurality of threaded shafts in the same direction, wherein drivingthe third gear in a first direction causes the articulation portion toarticulate in second plane.

According to another aspect of the present disclosure each pair ofthreaded shafts includes one left-hand threaded shaft and one right-handthreaded shaft. Further, the first and third gears may interface withplanetary gears to drive their respective pairs of threaded shafts, andeach threaded shaft may include a spur gear driven by internal gearteeth of said planetary gears.

In another aspect of the present disclosure the surgical instrumentincludes a control system. The control system may include at least oneprocessor and one memory for storing a control algorithm. Further thefirst, second, and third motors may include an encoder providingfeedback to the control system of the mechanical motion of the motor.

Another aspect of the present disclosure is a user input providingdesired end effector movement data to the control system, wherein saidcontrol system interprets the input end effector movement data andsignals one or more of the first, second, or third motors in accordancewith said end effector movement data.

According to a further aspect of the invention the control system mayinclude a control algorithm stored in the memory, for controlling themovement of the end effector in response to the input end effectormovement data. In one aspect of the invention, the algorithm and controlsystem synchronize the movements of the first, second, and third motorsand enable movement of the end effector and articulating portion inmultiple planes simultaneously.

The user input may be selected from the group consisting of a button, atoggle, a joystick, a pressure sensor, a switch, a trackball, a dial, anoptical sensor, and any combination thereof.

According to a further aspect of the invention, the surgical instrumentincludes an electrosurgical energy source, the electrosurgical energysource provides energy to one or more seal plates operably connected tothe end effector. The end effector is movable from an open position to aclosed position upon actuation of a movable handle, and application ofsaid electrosurgical energy is prevented until the end effector has beenmoved to the closed position. The surgical instrument may also include aknife for severing tissue following formation of a seal in said tissueby application of said electrosurgical energy.

These and other aspects of the present disclosure are described ingreater detail and set forth in the following drawings and detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1 is a perspective view of an endoscopic forceps showing a housing,a flexible shaft and an end effector assembly according to the presentdisclosure;

FIG. 2 is an enlarged front, perspective view of the flexible shaft andthe end effector assembly of FIG. 1;

FIG. 3 is an enlarged exploded rear perspective view of the flexibleshaft and end effector of FIG. 1;

FIG. 4 is a side cross section of the flexible shaft and end effectorassembly of FIG. 2 shown in an open configuration;

FIG. 5 is a side cross section of the flexible shaft and end effectorassembly of FIG. 2 shown in a closed configuration;

FIG. 6 is a side cross section of the flexible shaft and end effector ofFIG. 2 showing distal translational movement of a cutting mechanismconfigured to cut tissue disposed within jaw members of the end effectorassembly;

FIG. 7 is a longitudinal, cross-sectional view of the end effectorassembly of FIG. 2 in an un-articulated condition;

FIG. 8 is a longitudinal, cross-sectional view of the end effectorassembly of FIG. 2 in an articulated condition.

FIG. 9 is an enlarged perspective view of another partially flexibleshaft and end effector assembly according to the present disclosure;

FIG. 10 is an enlarged, exploded perspective view of the partiallyflexible shaft of FIG. 9;

FIG. 11 is a bottom perspective of the partially flexible shaft of FIG.10 with end effector assembly shown in partially open configuration;

FIG. 12 is a front perspective of the partially flexible shaft of FIG.10 with end effector assembly shown in closed configuration;

FIG. 13 is a top cross section of the partially flexible shaft of FIG.10 in an articulated orientation;

FIG. 14 is an enlarged front, top view of the flexible shaft and the endeffector assembly in an un-articulated condition according to anotheraspect of the present disclosure;

FIG. 15 is an enlarged exploded front perspective view of the flexibleshaft and end effector of FIG. 14;

FIG. 16 is an enlarged side view of the flexible shaft and end effectorof FIG. 14 in an upwardly articulated position;

FIG. 17 is an enlarged side view the flexible shaft and end effector ofFIG. 14 in a rightward articulated position;

FIG. 18 is an enlarged side view the flexible shaft and end effector ofFIG. 14 in a leftward articulated position;

FIG. 19 is a front perspective view of a shaft and steering unit of FIG.1, with the steering unit cutaway to show the internal mechanism;

FIG. 20 is a rear perspective view of a portion of a shaft and steeringunit of FIG. 1, with the steering unit cutaway to show the internalmechanism;

FIG. 21 is a front perspective view of a portion of a shaft and steeringunit of FIG. 1, with the steering unit, cutaway to show the internalmechanism and the first casing removed to show its internals;

FIG. 22 is a rear perspective view of a motor and planetary gearing ofFIG. 1 for driving steering cables.

FIG. 23 is a perspective view of a shaft according to one aspect of thepresent disclosure depicting reference coordinate systems and planes.

These and other aspects of the present disclosure will be discussed ingreater detail below.

DETAILED DESCRIPTION

The present disclosure relates to a powered endoscopic instrument suchas an endoscopic forceps utilizing an elongated, generally flexible andarticulating shaft. Another aspect of the present disclosure is directedto electrosurgical endoscopic devices and more particularly toendoscopic electrosurgical forceps for sealing and/or cutting tissueutilizing an elongated, generally flexible and articulating shaft. Inone embodiment, for example, such a device comprises a handle, handleassembly or other suitable actuating mechanism (e.g., robot, etc.)connected to a proximal end of a flexible, elongated body portion orshaft. A distal portion of the flexible shaft includes an articulatingportion comprised of one or more joints to allow articulation of an endeffector away from the longitudinal axis in response to actuation ofarticulation cables. An end effector is operatively supported on adistal end of the flexible shaft. The end effector includes a pair ofjaws that can be actuated between a closed position and an openposition. The jaws may be adapted to supply electrical energy to tissuegrasped between the jaws. The end effector may also include a knifeassembly that can be actuated to cut tissue grasped within the jaws.

The functions of opening and closing the jaws; operating the knifeassembly; and articulating the end effector can be performed remotelyfrom the handle by actuation of various mechanisms in the handle.Mechanical motion may be transmitted from the handle through theflexible shaft to the end effector by flexible or rigid cables or rodswithin the flexible shaft. For example, in one embodiment two cables areused to provide articulation; one push-pull style cable opens and closesthe jaws; and a second push-pull style cable actuates the knifeassembly. One aspect of the device of the present disclosure is adaptedto be placed in a lumen of a flexible endoscope and then inserted into anatural orifice of a patient and transited endoluminally through theanatomy of the natural lumen to a treatment site within or outside thenatural lumen. Alternatively, the device may be inserted into the bodyof a patient via a surgical port, or other means known to those of skillin the art. In the drawings and in the descriptions which follow, theterm “proximal,” as is traditional, will refer to the end of theelectrosurgical device and its components which is closer to the user,while the term “distal” will refer to the end which is farther from theuser.

FIG. 1 shows the general view of one aspect of the present disclosure.FIG. 1 depicts an endoscopic device 10. The endoscopic device includesan end effector 12 connected to a housing or body 14 via a shaft 16. Theshaft 16 is composed of an articulating portion 18, and anon-articulating portion 20. The articulating portion 18 of the shaft 16may be made of a series of moveable links, and will be discussed ingreater detail below. Shaft 16 contains steering cables and activationmembers like wires, rods, cables etc., for clamping, cutting, ordelivering energy to the end effector 12. As noted above shaft 16connects to body 14, and in particular connects to a steering unit 22.Shaft 16 may be formed of a rigid material such as stainless steel, oralternatively a flexible material such as plastic tubing and mayincorporate a tube of braided steel to provide axial (e.g., compression)and rotational strength.

Also housed within the body 14 is a control system 24, which may includea programmable microprocessor. Power is supplied to the endoscopicdevice 10 from an external source, such as an electrosurgical generator,via cable 26 or alternatively may be derived from local batteriesincorporated into the housing 14 (not shown). At least one electricalconnection 28 is used to power the control system 24. One of thefunctions of the control system 24 is to control the steering unit 22,and in particular to control the actuation of steering control motors,which are incorporated in to the steering unit 5, and will be discussedin greater detail below.

As shown in FIG. 1, an activation switch 30 is formed on the top of thebody 14 of the endoscopic device 10. The activation switch 30 enablesthe user or surgeon to input the desired commands to the control system24, which in turn drives the steering unit to effectuate articulationand/or rotation of the end effector 12. Additional activation elementsmay also be incorporated such as clamping handle 32 which can controlopening and closing of the end effector 12 in order to grasp tissue. Atrigger 34 may be provided to effectuate application of electrosurgicalenergy for sealing or cutting tissue held within the end effector 12.Additionally, or alternatively the trigger 34 may actuate a knife blade,as will be discussed in detail below.

It is contemplated that according to aspects of the present disclosurerelating to the use of electrosurgical energy for sealing or cuttingtissue the power source supplying power to cable 26 may be a generatorsuch as those sold by Covidien e.g., the LIGASURE™ Vessel SealingGenerator or the Force Triad™ Generator.

The generator may include various safety and performance featuresincluding isolated output, independent activation of accessories and/orso-called “Instant Response™” software which is a proprietary technologyowned by Covidien. Instant Response™ is an advanced feedback systemwhich senses changes in tissue 200 times per second and adjusts voltageand current to maintain appropriate power. The Instant Response™technology is believed to provide one or more of the following benefitsto vessel sealing: consistent clinical effect through all tissue types;reduced thermal spread and risk of collateral tissue damage; less needto “turn up the generator”; and designed for the minimally invasiveenvironment.

Turing now to FIG. 2, there is depicted a close-up view of the endeffector 12, and articulated portion 18. The articulated portion 18 isflexible and contains one or more moving joints 18 a. A flexible casingor sleeve (not shown) may be employed to protect a plurality of internalmoving joints 18 a of the articulated portion 18. Articulation of thearticulating portion 18, using the moving joints 18 a is accomplished bymanipulation of articulation cables 38 a, 38 b.

As mentioned above, end effector 12 is attached at the distal end of theendoscopic device 10 and includes a pair of opposing jaw members 40 and42. Movable handle 32 is connected to a drive assembly whichmechanically cooperates to impart movement of the jaw members 40 and 42from an open position wherein the jaw members 40 and 42 are disposed inspaced relation relative to one another, to a clamping or closedposition, wherein the jaw members 40 and 42 cooperate to grasp tissuethere between, as depicted in FIG. 2.

The end effector 12 may be designed as a unilateral assembly, i.e., jawmember 42 is fixed relative to the shaft 16 and jaw member 40 pivotsabout a pivot pin 44 to grasp tissue or a bilateral assembly, i.e., bothjaw members 40 and 42 move relative to a common axis A drive rod 46 ordrive sleeve is operably coupled to a drive assembly (not shown) andselectively reciprocable via movement of, for example moveable handle 32in the direction of fixed handle 36 to actuate, i.e., pivot, the jawmembers 40 and 42 relative to one another. In an embodiment of thedevice, drive rod 46 is flexible, and may be, for example, a cable.

According to the present disclosure and as best illustrated in FIG. 3, aknife channel 48 may be defined in the upper and/or lower jaw member 40and 42, respectively (though not shown in the upper jaw in FIG. 3). Theknife channel 48 is dimensioned to run through the center of the jawmembers 40 and 42, respectively, such that a blade 50 may be selectivelyreciprocated to cut the tissue grasped between the jaw members 40 and 42when the jaw members 40 and 42 are in a closed position. Blade 50 may beconfigured (or the blade 50 in combination with the end effector 12 ordrive assembly) such that the blade 50 may only be advanced throughtissue when the jaw members 40 and 42 are closed thus preventingaccidental or premature activation of the blade 50 through the tissue.

As best shown in FIGS. 2 and 3, jaw member 40 includes an insulative jawhousing 52 and an electrically conductive surface or seal plate 54.Insulator 52 is dimensioned to securely engage the electricallyconductive sealing surface 54 by stamping, by overmolding, byovermolding a stamped electrically conductive sealing plate and/or byovermolding a metal injection molded seal plate. All of thesemanufacturing techniques produce jaw member 40 having an electricallyconductive surface 54 which is substantially surrounded by an insulativejaw housing 52. Jaw member 40 may also include one or more wire guidesor channels (not shown) which are designed to allow a lead to be inelectrical continuity with sealing surface 54.

Jaw member 42 includes similar elements to jaw member 40 such as aninsulative jaw housing 56 and an electrically conductive sealing surfaceor seal plate 58 which is dimensioned to securely engage the insulativejaw housing 56. The electrically conductive surfaces 54, 58 and theinsulative jaw housing 52, 56, when assembled, include alongitudinally-oriented channel 48 defined there through forreciprocation of the knife blade 50. As mentioned above, when the jawmembers 40 and 42 are closed about tissue, knife channel 48 allowslongitudinal extension of the knife 50 in a distal fashion to severtissue along the tissue seal. A single knife channel, e.g., 48, may becompletely disposed in one of the two jaw members, e.g., jaw member 40or 42, depending upon a particular purpose. Jaw member 42 may beassembled in a similar manner as described above with respect to jawmember 40.

Jaw member 42 includes a series of stop members 60 disposed on the innerfacing surfaces of the electrically conductive sealing surface 56 tofacilitate gripping and manipulation of tissue and to define a gap “G”between opposing jaw members 40 and 42 during sealing and cutting oftissue. The preferred gap “G” between the conductive sealing surfaces 54and 58 to effectively and reliably seal tissue is between about 0.001and about 0.006 inches. Stop members 60 may be employed on one or bothjaw members 40 and 42 depending upon a particular purpose or to achievea desired result. Stop members 60 may be thermally sprayed atop theelectrically conductive sealing plate 58 or deposited or affixed in anyother known fashion in the art. Moreover, the stop members 60 may bedisposed in any configuration along the electrically conductive jawsurfaces 54 and 58 depending upon a particular jaw configuration ordesired surgical result.

An electrical lead (not shown) carries a first electrical potential tojaw member 40 and a second electrical potential is transferred throughdrive rod 46 (or, alternatively, the above mentioned sleeve) to jawmember 42. Upon activation, the two electrical potentials transmitelectrical energy through tissue held between conductive seal plates 54and 58.

Proximal movement of the drive rod 46 pivots the jaw members 40 and 42to a closed position. More particularly, to once actuated, handle 32moves in a generally arcuate fashion towards fixed handle 36 whichcauses reciprocating drive rod 142 to move in a generally proximaldirection to close the jaw members 40 and 42. In one embodiment proximalrotation of the handle 32 causes a locking flange associated withtrigger 34 to release, i.e., “unlock”, allowing for selective actuationof the knife 50. Once the tissue is grasped (within the requiredpressure range of about 290 kPa to about 1570 kPa), the user thenselectively applies electrosurgical energy to effectively seal tissue.Once sealed, the user then selectively advances the knife 50 byactuating the trigger 34 to cut the tissue along the tissue seal. In oneembodiment, for example, actuation of the trigger assembly 34 causes acable extending through shaft 16 and operatively coupled to knife 50 tomove distally to thereby cut tissue along the tissue seal. In anotherembodiment, trigger assembly includes gearing that translates actuationof the trigger assembly to rotational motion of a cable extendingthrough shaft 16.

As described above, with respect to FIGS. 2 and 3, the electrosurgicaldevice includes a plurality of joints 18 a which are nestingly arrangedin series to form flexible articulating portion 18. The distal end ofarticulating portion 18 mechanically engages the end effector 12 and theproximal end mechanically engages the shaft 20. Each of the plurality ofjoints 18 a of the flexible shaft 18 includes a distal knuckle 18 b anda proximal clevis 18 c formed therewith. Each knuckle 18 b operativelyengages a clevis 18 c of an adjacent joint 18 a. Each joint 18 a definesa central lumen 18 d formed therein and a pair of opposed lumens 18 eformed on either side of central lumen 18 d. Articulation cables 38 aand 38 b slideably extend through respective lumens 18 e of joints 18 a.The operation of cables 38 a and 38 b is explained in further detailbelow with respect to FIGS. 7 and 8.

As seen in FIG. 3, end effector 12 includes a jaw support member 62which is configured to pivotably support jaw members 40 and 42. Jawsupport member 62 defines a lumen 64 in a proximal end thereof and apair of spaced apart arms 66 a and 66 b in a distal end thereof. Lumen64 is configured and dimensioned to receive a stem 18 f extending from adistal-most joint 18 a of articulating portion 18 of shaft 16. Lumen 64includes a pair of opposed channels 68 a, 68 b in a surface thereofwhich are configured to slidingly receive the knife blade 50 forreciprocation therein.

Jaws 40 and 42 are pivotably mounted on support member 62 by a jaw pivotpin 70 which extends through apertures 72 formed in arms 66 a and 66 bof support member 62 and respective apertures 74 a, 74 b formed in jawmembers 40 and 42. To move jaws 40 and 42 between an open position and aclosed position, an axially or longitudinally movable center rod 76having a camming pin 78 is mounted within jaw support 62 at the distalend of center rod 76. Camming pin 78 rides in and engages angled cammingslots 80 a and 80 b formed in respective jaw members 40 and 42 such thataxial or longitudinal movement of the center rod 76 via drive rod 46causes jaws 40 and 42 to cam between open and closed positions.

End effector 12 includes a keyed rod 82 having a distal end rotatablyconnected to a proximal end of center rod 76. Keyed rod 82 includes aproximal end fixedly connected to a distal end of drive rod 46, and abody portion, disposed between distal end and proximal end, having anon-circular cross-sectional profile.

End effector 12 further includes a camming hub 84 having a lumen 86defined therethrough configured and adapted to slideably receive thebody portion of keyed rod 82 therein. Camming hub 84 includes a matingmechanical interface defined therein which cooperates with the outerperipheral configuration of body portion of keyed rod 82 to allowpositive engagement of the two component halves for rotational purposesas explained in more detail below. The camming hub 84 also includes ahelical or spiral groove 88 defined in an outer surface thereof which isconfigured to mechanically engage a detent protrusion 90 of the knife 50the purpose of which is also explained in more detail below. Camming hub84 is configured for rotatable disposition within lumen 64 of supportmember 62. In an alternative embodiment, camming hub 84 may be replacedby other mechanisms to translate rotational motion to linear motion(e.g., a lead screw, one or more gears, and the like).

In operation, the drive rod 46 is configured to provide two distinct andseparate functions: axial displacement thereof actuates the jaw members40 and 42 between the open to closed positions and rotational movementthereof advances the knife 50 through tissue. More particularly, axialdisplacement of drive rod 46 imparts axial displacement to keyed rod 82which, in turn, imparts axial displacement to center rod 76. However,since camming hub 84 slidably supports keyed rod 82, no axialdisplacement is imparted thereto, and keyed rod 82 is able to slidinglytraverse the camming hub 84 to impart axial force on the center rod 76.

As best shown in the progression from FIG. 4 to FIG. 5, proximaltranslation of the drive rod 46 in the direction of arrow “F” forcescamming pin 78 proximally within camming slots 80 a and 80 b to closethe jaw members 40 and 42 about tissue with the requisite closurepressure and within the requisite gap “G” range. In an alternativeembodiment (not shown), the functions actuated by drive rod 46 may bereversed with axial displacement advancing the knife 50 and rotationalmotion opening and closing jaw members 40 and 42. The electricallyconductive sealing plates 54, 58 are then energized to transmitelectrical energy through tissue held between the jaw members 40 and 42.

Once a proper tissue seal is formed, the tissue may be severed along thetissue seal. Again, one or more safety features may be employed toassure that a proper seal has been formed prior to severing tissue. Forexample, the generator may include a safety lockout which electricallyprevents or electro-mechanically prevents actuation of the knife 50unless a proper and effective seal has been formed. As mentioned above,it is also important to note that vessel or tissue sealing is more thansimply coagulating tissue and requires precise control of pressure,energy and gap “G” to effectively seal tissue.

As noted above the present disclosure incorporates a knife 50 which,when activated via the trigger 34, progressively and selectively dividesthe tissue along an ideal tissue plane in precise manner to effectivelyand reliably divide the tissue into two sealed halves. The knife 50allows the user to quickly separate the tissue immediately after sealingwithout substituting a cutting instrument through a cannula or trocarport.

It is envisioned that knife blade 50 may also be coupled to the same oran alternative electrosurgical energy source to facilitate separation ofthe tissue along the tissue seal. Moreover, it is envisioned that theangle of the blade tip of knife blade 50 may be dimensioned to providemore or less aggressive cutting angles depending upon a particularpurpose. For example, the knife blade 50 may be positioned at an anglewhich reduces “tissue wisps” associated with cutting. More over, theknife blade 50 may be designed having different blade geometries such asserrated, notched, perforated, hollow, concave, convex etc. dependingupon a particular purpose or to achieve a particular result. It isenvisioned that the knife 50 generally cuts in a progressive,uni-directional fashion (i.e., upon distal movement). As mentionedabove, the drive rod performs two functions, opening and closing the jawmembers 40 and 42 and advancing the knife 50 to sever tissue. In orderto sever the tissue, rotation of drive rod 46 imparts rotation to keyedrod 82 which, in turn, imparts rotation to camming hub 84. The distalend of the keyed rod 82 is allowed to rotate within the proximal portionof center rod 76. Thus center rod 76, which is connected at its distalend to camming pin 78 does not rotate.

End effector 12 is operably coupled to a knife 50 which is slidablysupported within respective channels 68 a and 68 b of support member 62.More particularly, knife 50 includes a sharpened or serrated edge at adistal end thereof and a pair of guide flanges proximally there from.The proximal end of knife blade 50 includes a protrusion 90 which isconfigured to engage and ride within spiral or helical groove 88 definedin camming hub 84.

In operation, as shown in FIG. 6, as camming hub 84 is rotated indirection of arrow “C”, proximal end 90 rides within groove 88 ofcamming hub 84 and moves in an axial direction “A” relative thereto.Rotation of the camming hub 84 in one direction forces the blade 50distally through knife channels 48 in jaw member 40 and/or 42 to severtissue disposed there between. Rotation in the opposite direction forcesproximal end 90 proximally to retract blade 50 to a proximal-mostposition. A spring may be operatively associated with the camming hub 84to bias the knife 50 in a proximal-most orientation.

As mentioned above, the end effector 12 may be selectively articulated.More particularly, as seen in FIG. 7 with end effector 12 in an axiallyaligned condition, in order to articulate end effector assembly 12 atleast one articulation cable (38 a, 38 b) operable from the body 14 isemployed. Each articulation cable (38 a, 38 b) includes a distal endoperatively connectable with an end effector 12 and a proximal endoperatively connected to at least one control element, such as, forexample a drive motor, as will be described in greater detail below. Inone example using two articulation cables 38 a, 38 b, movement of thecontrol element results in movement of the a first articulation cable 38a, wherein movement of the first articulation cable 38 a in a firstdirection causes an articulation of the end effector 12 in a firstdirection. Similarly, movement of the second articulation cable 38 b ina second direction results in articulation of the end effector 12 in asecond direction. This is generally referred to herein as a two-wirearticulation system and method.

More particularly and with reference to FIGS. 7 and 8, when firstarticulation 38 b cable (i.e., the lower articulation cable as depictedin FIGS. 7 and 8) is withdrawn in a proximal direction, as indicated byarrow “D” of FIG. 8, a distal end of articulation cable 38 b, anchoredto a distal-most joint 18 a of articulating portion 18, causes thejoints 18 a to rotate about the interface between knuckles 18 b andclevis' 18 c thereby causing gaps defined there between, along a sidesurface thereof, to constrict. In so doing, end effector 12 isarticulated in a downward direction, in the direction of arrow “B”,i.e., in a direction transverse to longitudinal axis. In order to returnend effector assembly 12 to an un-articulated condition or to articulateend effector assembly 12 in an opposite direction, articulation cable 38a (i.e., the upper articulation cable as depicted in FIGS. 7 and 8) mustbe withdrawn in a proximal direction and the force applied toarticulation cable 38 b must be released allowing it to move in theopposite direction.

Various handles and/or handle assemblies may be operatively connected orotherwise associated with end effector 12 in order to effect operationand movement of the various components thereof, i.e., drive cable 46and/or articulation cables 38 a, 38 b.

In one envisioned embodiment, the knife 50 may not be included with theendoscopic device 10 and the device may be designed solely for sealingvessels or other tissue bundles.

An alternative two wire end effector assembly and drive mechanism isshown in FIGS. 9-13. Many of the aforedescribed features of end effector12 and articulation portion 18 described above are similar to that ofend effector 112 and articulation portion 118 and for the purposes ofconsistency, these features are hereby incorporated in the followingdiscussion which is presented below in a more abbreviated form.

End effector 112 includes opposing jaw members 140 and 142 whichcooperate to effectively grasp tissue for sealing purposes. The endeffector 112 is designed as a unilateral assembly, i.e., jaw member 142is fixed relative to the articulation portion 118 and jaw member 140pivots about a pivot pin 144 to grasp tissue.

As shown in FIG. 10, a reciprocating sleeve 200 is slidingly disposedwithin the articulating portion 118 and is remotely operable by thedrive assembly (not shown). The pivoting jaw member 140 includes aprotrusion 202 which extends from jaw member 140 through an aperture 204disposed within the reciprocating sleeve 200 (FIGS. 10, 11). Thepivoting jaw member 140 is actuated upon by sliding sleeve 200 axiallywithin the coupling portion 206 such that a distal end of the aperture204 abuts against the protrusion 202 on the pivoting jaw member 140 (SeeFIG. 11). Pulling the sleeve 200 proximally closes the jaw members 140and 142 about tissue grasped there between and pushing the sleeve 200distally opens the jaw members 140 and 142 relative to one another forgrasping purposes.

End effector 112 may be structured such that electrical energy can berouted through the sleeve 200 to a protrusion 202 contact point with thesleeve 200 or using a “brush” or lever (not shown) to contact the backof the moving jaw member 140 when the jaw member 140 closes. In thisinstance, the electrical energy would be routed through the protrusion202 to one of the jaw members 140 or 142. Alternatively, an electricallead (not shown) may be routed to energize one of the jaw members, e.g.,jaw member 140, and the other electrical potential may be conductedthrough the sleeve 200 via an electrical contact with lead 208 (See FIG.11) and transferred to the pivoting jaw member 140 which establisheselectrical continuity upon retraction of the sleeve 200.

Jaw members 140 and 142 include similar elements to jaw members 40 and42 as described above such as jaw insulators 152, 156 and electricallyconductive sealing surfaces or seal plates 154 and 158, respectively.Jaw member 142 also includes a series of stop members 160 disposed onthe inner facing surface of electrically conductive sealing surface 158to facilitate gripping and manipulation of tissue and to define a gap“G” between opposing jaw members 140 and 142 during sealing and/orcutting of tissue. It is envisioned that the series of stop members 160may be employed on one or both jaw members 140 and 142 in a variety ofconfigurations depending upon a particular purpose or to achieve adesired result of the jaw. The stop members 160 insulate the jaw members140 and 142 preventing shorting and closing the circuit loop ininstances when there is no tissue between the jaws.

The end effector 112 may be articulated from an axially alignedcondition to an articulated condition. In order to articulate endeffector 112 via an articulation arrangement 118 similar to thearticulation arrangement described above, two articulation cables 138 aand 138 b may be utilized to articulate the articulating portion 118. Asbest seen in FIG. 11, each articulation cable 138 a and 138 b includes adistal end 210 a and 210 b which operatively connects with an endeffector 112 coupling assembly 206 disposed at the distal end ofarticulating portion 118. Coupling assembly 206 includes a cavity 212defined therein configured to receive a series of mechanicallyinter-cooperating elements 214 which are engaged by drive rod 146 forreciprocation therein as well as guide the various electricalconnections to the jaw members 140 and 146. The drive rod 146 ispreferably made from a flexible, friction-reducing material to allow thedrive rod 146 to bend in a given direction when the articulating portion118 of shaft 120 is articulated. The friction-reducing material reducesbuckling during articulation.

Coupling assembly 206 includes a pair of bushings 216 and 218 whichengage and secure a distal end of the drive rod 146 to the drive sleeve200 via pin 220. Bushing 216 is configured to engage bushing 218 andsecure the distal end of drive rod 146 there between. Pin 220 couplesthe secured bushings 216 and 218 and drive rod 146 to drive sleeve 200.The drive sleeve 200 (and secured drive rod 146) is received withincavity 212 for sliding translation therein upon actuation of the driveassembly (not shown).

Coupling assembly 206 also includes a locking element 222 which isconfigured to engage a proximal end of jaw member 142 to lock thecoupling assembly 206 (and drive rod 146) in fixed relation relative tojaw member 140 to limit any rotational movement there between.Longitudinal translation of the drive rod 146 in the distal directioncauses drive sleeve 200 to move longitudinally within the couplingassembly 206 and effectuate opening and closing of the jaw member 140,as described above. The coupling assembly 206 also includes a distalflange 224 which supports the lower jaw member 142 once assembled toconnected both jaw members 140, 142 to the coupling assembly 206 via pin226. As best shown in FIG. 11, the coupling assembly 206 also supportsthe electrical connection between lead 208 and driving sleeve 200. Inaddition, coupling assembly 206 also guides electrical lead 228 (shownin phantom in FIG. 12) therethrough for connection to jaw member 140. Asdetailed above, according to one embodiment of the disclosure one of theleads 208 and 228 may act as the active electrode, and the other act asthe return electrode in a typical RF energy system.

In operation, to articulate the articulation portion 118, as best shownin FIG. 13 when one cable 138 a is being pulled in the direction of P1,the other cable 138 b is being pushed (or relaxed) in the direction ofP2 to allow the articulation portion 118 to articulate in a givendirection. Similar to FIGS. 2 and 3 above, the articulating portion 118includes a plurality of joints 118 a which are nestingly arranged inseries. The distal end either directly or via coupling assembly 206mechanically engages the end effector 112 and the proximal end engages ashaft 120 (similar to the arrangement discussed above with respect toFIGS. 1-8). Each of the plurality of joints 118 a of the articulatingportion 118 includes a distal knuckle 118 b and a proximal clevis 118 cformed therewith. Each knuckle 118 b operatively engages a clevis 118 cof an adjacent joint 118 a. Each joint 118 a has a central lumen 118 ddefined therein and a pair of opposed lumens 118 e formed on either sideof central lumen 118 d. The articulation cables 138 a and 138 bslideably extend through respective lumens 118 e of joints 118 a. Thearticulation cables 138 a and 138 b are preferably made from a flexible,friction-reducing material.

It is envisioned that a safety mechanism or circuit (not shown) may beemployed such that the jaw members 140 and 142 cannot be energizedunless they are closed and/or unless the jaw members 140 and 142 havetissue held there between. In the latter instance, a sensor (not shown)may be employed to determine if tissue is held there between. Inaddition, other sensor mechanisms may be employed which determinepre-surgical, concurrent surgical (i.e., during surgery) and/or postsurgical conditions. The sensor mechanisms may also be utilized with aclosed-loop feedback system coupled to the electrosurgical generator toregulate the electrosurgical energy based upon one or more pre-surgical,concurrent surgical or post surgical conditions. U.S. patent applicationSer. No. 10/427,832 describes one such feedback system, the entirecontents of which being incorporated by reference herein.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, it is contemplated that the electrosurgicaldevice (and/or the electrosurgical generator used in connectiontherewith) may include a sensor or feedback mechanism (not shown) whichautomatically selects the appropriate amount of electrosurgical energyto effectively seal the particularly-sized tissue grasped between thejaw members 140 and 142. The sensor or feedback mechanism may alsomeasure the impedance across the tissue during sealing and provide anindicator (visual and/or audible) that an effective seal has beencreated between the jaw members 140 and 142. Examples of such sensorsystems are described in commonly-owned U.S. patent application Ser. No.10/427,832 entitled “METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RFMEDICAL GENERATOR” filed on May 1, 2003 the entire contents of which arehereby incorporated by reference herein.

In embodiment relating to both end effector 12 and 112, the electricallyconductive sealing surfaces 54, 154 and 58, 158 of the jaw members 40,42 and 140, 142, respectively, are relatively flat to avoid currentconcentrations at sharp edges and to avoid arcing between high points.In addition and due to the reaction force of the tissue when engaged,jaw members 40, 42 and 140, 142 can be manufactured to resist bending.For example, the jaw members 40, 42 and 140, 142 may be tapered alongthe width thereof which resists bending due to the reaction force of thetissue. In fact, in some circumstances tapering promotes visualizationand allows a greater bend radius than a jaw with a constantcross-section.

It is envisioned that the outer surface of the end effectors 12, 112 mayinclude a nickel-based material, coating, stamping, metal injectionmolding which is designed to reduce adhesion between the jaw members 40,42 and 140, 142 with the surrounding tissue during activation andsealing. Moreover, it is also contemplated that the conductive surfaces54, 58 and 154, 158 of the jaw members 40, 42 and 140, 142,respectively, may be manufactured from one (or a combination of one ormore) of the following materials: nickel-chrome, chromium nitride,MedCoat 2000 manufactured by The Electrolizing Corporation of OHIO,inconel 600 and tin-nickel. The tissue conductive surfaces 54, 58 and154, 158 may also be coated with one or more of the above materials toachieve the same result, i.e., a “non-stick surface”. As can beappreciated, reducing the amount that the tissue “sticks” during sealingimproves the overall efficacy of the instrument.

One particular class of materials disclosed herein has demonstratedsuperior non-stick properties and, in some instances, superior sealquality. For example, nitride coatings which include, but not are notlimited to: TiN, ZrN, TiAlN, and CrN are preferred materials used fornon-stick purposes. CrN has been found to be particularly useful fornon-stick purposes due to its overall surface properties and optimalperformance. Other classes of materials have also been found to reducingoverall sticking. For example, high nickel/chrome alloys with a Ni/Crratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 54, 58 and 154, 158 made from or coated with Ni200,Ni201 (˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

Endoscopic device 10, including end effectors 12 and 112 (either with orwithout articulating portions 18, 118, and shaft 3, 103) may be designedsuch that they are fully or partially disposable depending upon aparticular purpose or to achieve a particular result. For example, endeffector 12, 112 may be selectively and releasably engageable with thedistal end of the articulation portion 18, 118 and/or the proximal endof shaft 3, 103 may be selectively and releasably engageable with thehousing 14 of the endoscopic device 10. In either of these twoinstances, the endoscopic devices 10 would be considered “partiallydisposable” or “reposable”, i.e., a new or different end effectorassembly 12, 112 selectively replaces the old end effector assembly 12,112 as needed. As can be appreciated, the presently disclosed electricalconnections would have to be altered to modify the instrument to areposable design.

As noted above, other methods of controlling an articulating portion 18,118 of an electro surgical device are known and described in commonlyassigned U.S. Published Patent Application Nos. 2009/0054734 and2010/0179540, the contents of which are incorporated herein byreference. These control systems, in contrast to those described indetail above, incorporate what is referred to herein as a four-wiresystem. As a result of using four wires, these systems are able moreclosely approximate true wrist articulation. Devices employing suchsystems are able to not only articulate the end effector in a singleplane, and then rotate the entire shaft, but to actually articulate theend effector in multiple (e.g. up and down and side to side and anycombination thereof). When used in combination with the ability torotate the end effector, such they are able to closely mimic the degreesof freedom seen in the human wrist.

As these four-wire control systems employ very similar features as thetwo wire control systems described above, to the extent possible similarnumber will be used to describe control and articulation of anendoscopic device 10.

FIG. 14 depicts a perspective view of a shaft 216 and end effector 212.The shaft 216 includes an articulating portion 218 and anon-articulating portion 220. As above the non-articulating portion 220may exhibit various constructions. For example, the non-articulatingportion 220 may be formed from a substantially rigid tube, from flexibletubing (e.g., plastic), or the non-articulating portion 220 may beformed as a composite of a flexible tube and a rigidizing element, suchas a tube of braided steel, to provide axial (e.g., compression) androtational strength. In other embodiments, the non-articulating portion220 may be constructed from a plastically deformable material. In someembodiments the non-articulating portion 220 exhibits a flexuralrigidity that is sufficiently low to permit a surgeon to pre-shape orreshape the non-articulating portion 320 prior to or during a surgicalprocedure to accommodate the contours and characteristics of thesurgical site. Once shaped, the non-articulating portion 220 may definea non-aligned configuration wherein the longitudinal axis of thenon-articulating portion 220 is not aligned with the longitudinal axisof the articulating portion 218. The non-articulating portion 220 mayalso exhibit an axial rigidity that is sufficient to maintain the shapeand orientation of the non-aligned configuration during normal surgicaluse of the endoscopic instrument 10.

As shown in FIG. 15 the articulating portion 218 of shaft 216 mayinclude an exterior casing or insulating material 400 disposed over aplurality of links 218 a, 218 b. The links 218 a and 218 b areconfigured to pivot relative to one another to permit the articulatingportion 218 of the shaft 216 to articulate relative to its longitudinalaxis. In one embodiment, the links 218 a and 218 b are nestingly engagedwith one another to permit pivotal motion of the articulating portion218 in two orthogonal planes in response to movement of an articulationcontrol system, not shown.

Links 218 a are similar in construction to links 218 b in that each link218 a, 218 b exhibits a pair of distal knuckles 218 c and pair ofopposing proximal devises 218 d formed therewith. Links 218 a, however,are oriented with a ninety degree)(90° radial offset with respect to theneighboring link 218 b. Such an alternating orientation of the links 218a, 218 b facilitates articulation of the end effector 212 in orthogonalplanes. The horizontal knuckles 218 c of links 218 a define a horizontalpivot axis P1. Thus a knuckle 218 c of a link 218 a operatively engagesa corresponding clevis 218 d of a neighboring link 218 b to facilitatearticulation of the end effector 212 in the direction of arrows “U, D”(FIG. 16). Similarly, the knuckles 218 c of links 218 b define avertical pivot axis P2 such that a knuckle 218 b operatively engages acorresponding clevis 218 d of a neighboring link 218 a to facilitatearticulation of the end effector 212 in the direction of arrows “R, L”(as shown in FIGS. 17, 18)

Each link 218 a and 218 b includes a central lumen 218 e extendinglongitudinally therethrough. The central lumen 218 a permits passage ofvarious actuators, e.g., drive rod 246 and knife rod 250, and othercomponents through the elongated shaft 216. Links 218 a, 218 b alsodefine two pairs of opposed lumens 218 f and 218 g formed radiallyoutward from the central lumen 218 e. Each of the lumens 218 f and 218 gon a link 218 a is radially spaced at a 90° from the neighboring lumen218 f and 218 g such that each lumen 218 f aligns with a lumen 218 g ofa neighboring link 218 b. The lumens 218 f and 218 g cooperate to definea longitudinal cavity to permit passage of four steering cables 238 a,238 b, 238 c, and 238 d through the articulating portion 218 of theelongated shaft 216. A differential tension may be imparted to the foursteering cables 238 a-d to adjust the orientation of the articulatingportion 218 of shaft 216 as described below.

A link support 402 includes a pair of distal knuckles 218 c orientedsimilarly to a link 218 a to interface with a trailing link 218 b. Aproximal end of the link support 402 may be fixedly mounted to an outercasing 400, which in one embodiment extends only over the proximalportion 220 of the elongated shaft 216, however, in a furtherembodiment, the outer casing 400 extends over both the proximal portion220 and the articulating portion 218 of the shaft 216. The outer casing400 is generally flexible to permit the proximal portion 220 to flex andbend freely. An end effector support 404 may include a pair of clevises218 d on a proximal end oriented similarly to the clevises on link 218 ato receive the knuckles 218 c of a leading link 218.

The four steering cables 238 a-d may be substantially elastic andslideably extend through lumens pairs 218 f and 218 g defined in thelinks 218 a and 218 b. A distal end of the each of the steering cables238 a-d is coupled to the end effector support 404. More particularly,each steering cable 238 a-d includes a ball-like mechanical interface atthe distal end, namely, interfaces 238 a′-d′. Each interface 238 a′-d′is configured to securely mate within a corresponding recess defined inthe end effector support 404. 238 a′ engages recess 406 a, interface 238b′ engages recess 406 b, and interfaces 238 c′ and 238 d′ engage similarrecess on the end effector support 404.

The proximal ends of the steering cables 238 a-d are operatively coupledto the articulation controls as described below. The steering cables 238a-d extend through the proximal portion of shaft 220 through a series ofpassageways defined therein. More particularly, a cross-shaped cableguide adapter 408 and guide adapter liner or washer 410 include boresdefined therethrough to initially orient the cables 238 a-d at 90°degree angles relative to one another for passage into proximal portionof shaft 220. The adapter 408 also facilitates attachment of theproximal portion of shaft 220 to the housing 14 (FIG. 1). The proximalportion of shaft 220 includes passageways 412 a-d defined therein toorient the cables 238 a-d, respectively, for reception into the lumens218 f, 218 g of links 218 a and 218 b for ultimate connection to the endeffector support 404 as described above.

A central guide tube 414 is provided to orient the drive rod 246 and aknife rod 416 through the shaft 216 for ultimate connection to jawmember 240 and a knife 250. The central guide tube 414 may also guideelectrical leads 416 providing electrosurgical energy to the jaw member240, 242. The central guide tube 414 is dimensioned for reception withinproximal portion 220 of the shaft 216 310, and may extend distally therefrom into the central lumen 218 e defined in the links 218 a and 218 b.One or more steering cables, e.g., 238 a, include a distal portion 238a′ that electrically connects to the end effector support 404 which, inturn, connect to jaw member 240. A return path (i.e., ground path) maythus be established through tissue captured between jaw members 240 and242 for electrosurgical energy provided through jaw member 240.

The central extrusion or guide tube 414 is constructed from a highlyflexible and lubricious material and performs several importantfunctions: Guide tube 414 guides the drive rod 246, the knife rod 418and the electrical lead 416 from the guide adapter 408, proximal portion220 of shaft 216 and articulating portion 218 to the end effectorsupport 404 and knife 50; the guide tube 414 provides electricalinsulation between component parts; the tube 414 keeps the lead 416 androds 246 and 418 separated during relative movement thereof; the tube414 minimizes friction and clamping force loss; and tube 414 keeps thelead 416 and rods 246 and 418 close to the central longitudinal axis tominimize stretching during articulation. The tube 414 (and internallumens) may be made from or include materials like polytetrafluoroethene(PTFE), graphite or other lubricating agents to minimize friction andother common losses associated with relative movement of componentparts. Alternatively, a coaxial structure (not shown) may be utilized toguide the drive rod 246 and knife rod 418.

One or more distal guide plates 420 and an adapter 422 may also beutilized to further align the drive rod 246 and knife rod 418 andfacilitate actuation of the jaw members 240 and 242. More particularly,alignment of the drive rod 246 facilitates opening and closing the jawmembers 240, 242. A sleeve 424 includes an aperture 426 to engage aflange 428 of jaw member 240 such that axial movement of the sleeve 424forces jaw member 240 to rotate around pivot pin 430 and clamp tissue.Sleeve 424 connects to adapter 422 which secures drive rod 246 thereinvia a wire crimp 432. The drive rod 246 has a flat at a distal endthereof to reinforce attachment to crimp 432. By actuating movablehandle 32 (FIG. 1), the drive rod 246 retracts sleeve 424 to close jawmember 240 about tissue. Pulling the sleeve 424 proximally closes thejaw members 240 and 242 about tissue grasped there between and pushingthe sleeve 424 distally opens the jaw members 240 and 242 for graspingpurposes. The end effector 212 is designed as a unilateral assembly,i.e., jaw member 242 is fixed relative to the shaft 216 and jaw member240 pivots about a pivot pin 430 to grasp tissue. Other features of thejaw members 242, 240, their construction and method of manufacturing,their electrical connection and insulative properties, the use of aknife channel, and the methods of maintaining a proper gap are similarto those methods discussed above with respect to the two-wire controlsystems and are incorporated in connection with the features of thefour-wire design as if restated fully here.

Having described herein various aspects of both a two-wire and afour-wire articulation system for use in endoscopic device 10, thefollowing description is generally related to a motorized control systemfor effectively enabling one handed operation of the electrosurgicaldevice. Such operation should include one handed grasping of tissue,articulation of the end effector in at least two planes, activating theuse of electrosurgical energy, and where appropriate the activation of aknife for severing of tissue sealed by the electrosurgical energy.

As noted above, FIG. 1 depicts a steering unit 22. FIG. 19 shows themain components of steering unit 22. The steering unit 22 is housed inhousing or body 14 and is mounted on a bracket 502 which integrallyconnects to the housing or body 14. The shaft 20 connects to and in oneembodiment forms an integrated unit with internal casings 504 a and 504b, and connects to a spur gear 506. This integrated unit is, in oneembodiment rotatable in relation to the housing 14, such that the shaft20, internal casings 504 a-b, and spur gear 506 can rotate about shaftaxis “z”. The shaft 20 and integrated internal casings 504 a-b aresupported radially by bearings 508, 510, and 512.

An electric motor 514R, in one embodiment, includes an encorder forconverting mechanical motion into electrical signals and providingfeedback to the control system 24. Further, the electric motor 514R (Rindicates this motor if for inducing rotation of the shaft 20 and endeffector 12) may include an optional gear box for increasing or reducingthe rotational speed of an attached spur gear 515 mounted on a shaftdriven by the electric motor 514R. Electric motors 514LR (LR referringto left-right movement of the articulating portion 18) and 514UD(referring to up-down movement of the articulating portion 18), eachoptionally includes an encoder and a gearbox. Respective spur gears 516and 518 drive up-down and left-right steering cables, as will bedescribed in greater detail below. All three electric motors 514 R, LR,and UD are securely attached to the stationary frame 502, to preventtheir rotation and enable the spur gears 515, 516, and 518 to be drivenby the electric motors.

FIGS. 21 and 22 depict details of the mechanism causing articulatingportion 18, and therewith the end effector 12 to articulate.Specifically, the following depicts the manner in which the up-downarticulation is contemplated in one aspect of the invention. Such asystem alone, coupled with the electric motor 514UD for driving the spurgear 506 would accomplish articulation as described above in a two-wiresystem. However, where a four-wire system is contemplated, a secondsystem identical to that described immediately hereafter, can beemployed to drive the left-right cables. Accordingly, for ease ofunderstanding just one of the systems is described herein, with theunderstanding that one of skill in the art would readily understand howto employ a second such system in a four-wire system.

To accomplish up-down articulation of the articulating portion 18 andtherewith the end effector 12, as in the systems described above,steering cables 38 a-b, 138 a-b, or 238 a-b may be employed. For ease ofunderstanding, the following will only reference one of the articulationsystems described above, but any of they may be employed herein withoutdeparting from the scope of the present invention. The distal ends ofthe steering cables 38 a-b are attached to, or at, or near the proximalend of the end effector, by the means described above. The proximal endsof the steering cables 38 a-b are attached to the distal tips of theposts 520 a, and 520 b. As shown in FIG. 21, the posts 520 a and 520 breciprocate longitudinally, and in opposing directions. Movement of theposts 520 a causes one steering cable 38 a to lengthen and at the sametime, opposing longitudinal movement of post 520 b causes cable 38 b toeffectively shorten. The combined effect of the change in effectivelength of the steering cables 38 a-b is to cause joints 18 a forming thearticulating portion 18 of shaft 16 to be compressed on the side inwhich the cable 38 b is shortened, and to elongate on the side in whichsteering cable 38 a is lengthened. This is effectuated by the integratedknuckles and devises describe above.

The posts 520 a-b slide on an internal frame 504 c formed internally toand integrally with casing 504 a. Both the internal frame 504 c and theposts 520 are preferably formed of a resilient, non-binding, lowfriction material of the type described herein above to promoteefficient and smooth travel of the posts 520 a-b along the correspondingand cooperating portions of the internal frame 504 c.

The opposing posts 520 a and 520 b have internal left-handed andright-handed threads, respectively, at least at their proximal ends. Asshown in FIG. 22. housed within casing 504 b are two threaded shafts 522a and 522 b, one is left-hand threaded and one right-hand threaded, tocorrespond and mate with posts 520 a and 520 b. The shafts 522 a and 522b have distal ends which thread into the interior of posts 520A and 520Band proximal ends with spur gears 524 a and 524 b.

The shafts 522 a and 522 b have freedom to rotate about their axes. Thespur gears 524 a and 524 b engage the internal teeth of planetary gear526. The planetary gear 526 also an external teeth which engage theteeth of spur gear 518 on the proximal end of electric motor 514UD.

To articulate the end effector 12 in the upwards direction, a user orsurgeon activates via the activation switch 30 the electric motor 514UDcausing it to rotate the spur gear 518, which in turn drives theplanetary gear 526. The planetary gear 526 is connected through theinternal gears 524 a and 524 b to the shafts 522 a and 522 b. Theplanetary gear 526 will cause the gears 524 a and 524 b to rotate in thesame direction. The shafts 522 a and 522 b are threaded, and theirrotation is transferred by mating threads formed on the inside of posts520 a and 520 b into linear motion of the posts 520 a and 520 b.However, because the internal threads of post 520 a are opposite that ofpost 520 b, one post will travel distally and one will travel proximally(i.e., in opposite directions) upon rotation of the planetary gear 526.Thus the upper cable 38 a is pulled proximally to lift the end effector,while the lower cable 38 b must be relaxed. As stated above, this samesystem can be used to control left-right movement of the end effector,using the electric motor 514LR, its spur gear 516, a second planetarygear 526, and a second set of threaded shafts 522 and posts 520 and twomore steering cables 38. Moreover, by acting in unison, a systememploying four steering cables can approximate the movements of thehuman wrist by having the three electric motors 514 and their associatedgearing and steering cables 38 computer controlled by the control unit24. Such a system is described in greater detail below.

In use, if the end effector 12 has been articulated such that it is inthe up position, e.g., bent approximately 90° from its longitudinalaxis, and then the electric motor 514R is energized, then shaft 3 willrotate and the articulated tip will start moving to the left or rightposition of its original position. In some instances such a rotationwill be desirable to the surgeon. However, in other situations it willnot be desirable, or in the performance of more complicated maneuversthere will be a desire to maintain some aspect of the end effector'sposition and enable wrist-like movement of the articulating portion 18without changing the orientation of the end effector 12, perhaps toenable some subsequent action that depends upon repositioning of thearticulating portion 18 before it can be performed. To accomplish thisaspect of the present disclosure the actions of all three electricmotors 514R, LR, and UD must be synchronized by the control system 24.

In the synchronized mode, when the motor 514R rotates the shaft 3 byspecific angular increment, this increment is identified by the motorencoder and is sent to the control unit 24. The control unit 24calculates correction increments and orders the motors 514UD, 514LR totension and relax as necessary their respective steering cables 38 suchthat the end effector 12 remains in the up position while thearticulating portion rotates to a desired position, defined by the totalrotation of the motor 514R.

As described above, the control unit 24 contains a processing unit,(e.g., a microcontroller), a user interface through which the surgeonspecifies the desired action and a motor interface. The user interfacereceives user commands from activation switch 30, which may be adirectional button, a joystick such as a thumb operated joystick, atoggle, a pressure sensor, a switch, a trackball, a dial, a opticalsensor, and any combination thereof. The processing unit responds to theuser commands by sending control signals to the motors 514. The encodersof the motors 514 provide feedback to the processing unit 24 about thecurrent status of the motors 514.

An algorithm, employed to maintain the position of the end effector 12while rotating the shaft 16 is incorporated into software stored in amemory portion of the of control unit 24. Thus the end effector 12 canbe wrist rotated by applying different motor positions of the steeringcables in the orthogonal planes.

Multiple plane articulation and rotation controlled by independent stepmotors, as described above, can result in a number of tip motions, allof which can be synchronized by the control system 24, which may be forexample a microprocessor. To clarify the types of motions possible it isuseful to consider an additional coordinate system.

As depicted in FIG. 23, the first system XYZ is stationary with axis Xsubstantially aligned with the center axis of non-articulating portion20 of the shaft 16. Additionally shown is a plane P aligned with theclamping surface of the stationary jaw 42 of the end effector 12, thepoint is A located on the center axis of the end effector 12, and theaxis “U” is aligned with the center axis of the end effector 12.

In operation, the motor 514LR acting independently can articulate theend effector 12 to the left or right in the XY plane with the plane P(and the clamping surface of the stationary jaw 42) substantiallyorthogonal to a plane XZ. The motor 514UD, acting independently, canarticulate the end effector 12 up and down in the plane XZ with theplane P substantially orthogonal to the plane XZ. Thus, operating themotors 514UD and 514LR independently the user can articulate the tip todesired position in the 3D space with the plane P generally orientedorthogonally to the plane XZ.

However, synchronized 3D articulation of the end effector 12, whendriven by motors 514UD and 514LR simultaneously (or in a coordinatedfashion) and controlled by the control system 24 microprocessor, allowsmovement of the end effector 12 such that the tip can move alongprescribed path. For example the tip can articulate along a circle inCCW direction, with the plane P still generally normal to XZ.

Alternatively, the synchronized motion can incorporate rotational motionimparted by motor 514R which rotates the articulated shaft 16 CW.According to one aspect of the present disclosure, the motors 514UD and514 LR can simultaneously (or in a coordinated fashion) articulate theend effector 12 CCW, in the manner described above, to negate therotational motion. As the result, point A of the end effector 12 willstop moving, however, the end effector 12 as well as the plane P andflat surface of the stationary jaw 42 will rotate around axis “U.” Thismotion called wrist-rotation allows the user to rotate the jaws inchosen articulated position. Such wrist-rotation is, according to thepresent disclosure, achieved without mechanical rotational connection ofthe end effector 12 with respect to the rest of the shaft 16 andeliminates the need for slip rings in this area if electrical energy isto be supplied to the jaws.

Further, by rotating the shaft 16 with the motor 514R (and compensating“back drive” of the reciprocating posts 520 with the synchronized motionof the motors 514UD and 514 LR purely rotational motion of the shaft inwhich plane P rotates around axis X can be achieved. As can be seen, theproposed system allows wide range of the motion of the distal tip whichcan be executed in hand held device or robotic arm.

Though disclosed herein with respect to a handheld electrosurgicaldevice, those of skill in the art will readily understand that themethods and mechanism disclosed herein is readily applicable for use asa component in a robotic surgical device wherein the electrosurgicaldevice is held by or incorporated into a remotely operated surgical arm.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed is:
 1. A surgical instrument for treating tissue,comprising: a housing having a shaft extending there from, said shaftincluding at least an articulating portion and an end effector; a firstcasing connected to and rotatable with the proximal end of said shaft;an internal frame housed within the first casing; a plurality of posts,supported by the internal frame and connected on their distal ends to atleast one drive wire, and connected on their proximal ends to a threadedshaft; a second casing connected to the first casing and rotatabletherewith, said second casing housing the threaded shafts; a firstelectric motor driving a first gear, said first gear interfacing withthe threaded shafts such that a first pair of the plurality of threadedshaft rotate in a same direction; a second electric motor driving asecond gear, said second gear causing the connected shaft and first andsecond casings to rotate about a common axis; wherein driving said firstgear in a first direction causes said articulating portion to articulatein a first plane.